Heat pump



Nov. l, 1960 FIGI A B. G. EGON HEAT PUMP Filed Nov. 3, 1958 A I l l BTU/Ib.

HIGH GAS LOW LIQUID HIGH LIQUID l HIGHER LIQUID FIG. 2

INVENTOR.- BASIL G. EGON loam/af ATT'YS inw HEAT PUMP Basil G. Egon, 6739 N. lonia, Chicago, Ill.

Filed Nov. 3, 1958, Ser. No. 771,285

11 Claims. (Cl. 62-197) This invention relates to heat pumps, and more particularly to improved means for increasing the efficiency of heat pumps.

Heretofore, heat pumps have never been widely accepted because of their low efficiency and costly operation, especially in the northern climates. With the subsequent development of more efficient compressors, the heat pump found some application in the warmer climates, but still proved undesirable in the northern climates because of low eiiiciency and high operational costs.

The present invention overcomes the above problems by reducing the amount of work to be done per unit of refrigeration or per unit of heating accomplished. Thus, the efficiency of the heat pump has been greatly increased by the present invention. This is made possible by intercooling the refrigerant in the compressor while nited States Patent() it is being compressed in an effort to follow the vapor saturation line by injecting a predetermined amount of refrigerant directly into the compressor starting at the beginning of the compression and ending before the end of compression.

Accordingly, it is an object of this invention to provide an improved heat pump having an efficiency greater than any heat pump heretofore developed.

Another object of this invention resides in the provision of a heat pump having means for reducing the -amount of work to be done per unit of refrigeration or per unit of heating accomplished.

Still another object of this invention is in the provision of a heat pump having means for intercooling the refrigerant in the compressor while it is being compressed.

A further object of this invention is to provide a heat pump having means for injecting a predetermined amount of refrigerant directly into the compressor starting at the beginning of the compression and ending a little before the end of compression.

A still further object of this invention is to provide a heat pump having a refrigerant charging unit for injecting a predetermined amount of liquid refrigerant into the compressor during the compression stroke and in response to the compression stroke.

A still further object of this invention is in the provision of a heat pump having a refrigerant injection unit operable in response to the compressor for injecting a measured charge of liquid refrigerant under high pressure into the compressor, whereby the injection unit may be adjusted to vary the amount of charge injected into the compressor.

Other objects, features, and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheet of drawings, wherein like reference numerals refer to like parts, in which:

Fig. l is a diagrammatic view of a heat pump according to the invention and illustrating a vertical sectional view of the refrigerant injection unit with the parts positioned prior to the initiation of the compression stroke in the compressor;

Patented Nov. 1, 1.960

Fig. 2 is a fragmentary view of the heat pump, illustrating the positions of the parts during the compression stroke, when a measured charge of refrigerant is injected into the compressor; and

Fig. 3 is a pressure-enthalpy diagram illustrating the thermodynamic processes involved when comparing the straight compression process heretofore known and the intercooling process of the present invention.

Referring now to the drawings, and particularly to Fig. 1', the heat pump of the present invention includes generally a compressor 10, a condenser 11, and an expansion or throttling valve 12, an evaporator 13, and a refrigerant injection unit 14.

The compressor 10 is of the reciprocating type and includes a piston 1S reciprocable in a cylinder 16 and defining a compression chamber 17. It may be appreciated that other types of compressors may be employed, although the present invention will be hereinafter described in connection with a reciprocating compressor.

Low pressure gas refrigerant is conveyed from the evaporator to the compressor by a line or conduit 18. This low pressure gas refrigerant is then compressed by the compressor and conveyed through the line 19 to the condenser 11. The high pressure gas refrigerant is condensed by the condenser thereby giving off heat and lowering its temperature. The high pressure liquid refrigerant is then conveyed to the evaporator 13 through a line or conduit 20. As the high pressure liquid refrigerant passes through the expansion or throttle valve '12, its pressureis reduced prior to entering the evaporator. The liquid refrigerant is then evaporated in the evaporator by adsorption of heat and low pressure gas is returned to the compressor through the line 18.

The refrigerant injection unit 14 includes a casing 21 having large and small connected stepped bores 22 and 23 slidably receiving therein a floating piston 24 having large and small stepped portions 25 and 26. The casing is closed at one end by an end wall 27 and at the other end by an end wall 28. The free end of the piston portion 25 defines with the end wall 27 a working chamber 29 intercommunicating directly with the compression chamber 17 of the compressor 10 by a line or conduit 30.

Upper and lower annular shoulders having resilient rings 31 and 32 of neoprene, rubber, plastic or equivalent suitable material are provided within the larger bore 22 for determining the limits of movement of the piston 24 and for cushioning movement of the plunger to reduce shock and noise. Additionally, an adjustable stop 33 is threadedly received in the end wall 27 and adapted to engage the lower end of the piston 24 to further limit the movement of the piston adjustably to vary the measured charge to be injected into the compressor as will be hereinafter more clearly explained. A resilient pad 33a of neoprene, rubber, plastic or equivalent suitable material is secured to the piston engaging end of the stop 33 to cushion the return stroke of the piston. A venting chamber 34 is defined above the larger piston poltion 25 and intercommunicated with the low pressure return line 18 by a line or conduit 35.

At the upper end of the casing, a necked or restrictive portion 36 is spaced inwardly from the end wall 28 and defines a seat for a check valve member 37 resiliently biased thereagainst by a spring 3S and defining a check valve. The check valve defines with the free end of the piston portion 26 a charge chamber 39 intercommunicated with a source of high pressure liquid refrigerant by means of a line or conduit 40 extending to the line 20 ahead of the expansion valve 12. A one-way or check valve 41 is arranged in line 40 to permit flow of refrigerant to the charge chamber 39, but prevent backflow through the line 40.

The discharge side of the check valve 37 is intercom- 3 4 municated with the compression chamber 17 of the comjection unit and the quality of this diverted refrigerant pressor by means of a line or conduit 42 and this check as follows:

valve only permits flow toward the compressor.

Springs 43 and 44 are received in the casing and act A' Quahty of Iefngerant at pomt H3:

on opposite sides of the larger piston portion 25 to aid in 5 H3-H 3l.16- 17 .00 215 maintaining the piston oating in the casing. The spring -Hi- H-ggjl- 17.00"' 44 is slightly stronger than the spring 43 and serves to return the piston to normal position Iafter it has injected a B. Work necessary for the intercooling process= measured charge of refrigerant into the compressor.

It will be appreciated that the refrigerant injection H1 H5-90'S5 8862-2'23 BML/1b" unit of the present invention which provides the inter- C. Weight of refrigerant necessary to cool 2.23 cooling process may be employed with single or multi- B.t.u./lb.= stagle compressors, although shown and described herein H1 H5 2 23 0 o 1b /lb wit a single stage unit. 402

Operation of the heat `pump and the refrigerant injec (lxmH'He) (1 215) (8271-17'00) of refrigtion unit of the present invention is initiated at the be- @Tant ginning of the compression stroke of the compressor 10, when the piston 15 begins its upward movement to com- D' Welght of refngerant passmg through evaporatorpress the low pressure gas in the compression chamber 17. W=l-0.0432=.9568 lbs. It will be appreciated that the charge chamber 39 is al- 20 ready lled with high pressure liquid refrigerant deliv- Now the refrigeration and coeiiicient of performance ered through the line from the discharge side of the of the thermodynamic process according to the present condenser. As the low pressure gas is compressed in the invention may be Calculated aS OHOWSI l. Work =H5H4=88.6282.71 =5.91 B.t.u./llb. 2. Refrigeration =(H4-H2)W=(82.71-3l.16)0.9568=49.40 B.t.u./b.

refrigeration* 49.40 3. Coefficient of performance- Work --591 8.34 B.t.u./lb.

compression chamber 17, this pressure is reflected in the Accordingly, the amount of work necessary to ac comworking chamber 29 to act on the lower end of the piston plish the same amount of refrigeration with the inter- 24, forcing it upwardly to discharge the refrigerant charge 35 cooling compression process of the present invention is in the charging chamber 29 therefrom by un'seating the 5.9l B.t.u. off work per pound of refrigerant. r[ 'his .1s check valve 37, as seen in Fig. 2, and forcing the charge considerably less than 8.14 B.t.u./1b., that 1s requlred 1n of liquid refrigerant into the compressor in the form of the straight Compression Process finely atomized droplets which evaporate in the lower Assuming the compressor efficiency is 80% Vand the pressure environment. This evaporation cools the oom- 4o refrigerant injection unit eiciency is 80%, the net ellipressed gas refrigerant with an overall gain in efficiency ciency increase may be calculated as follows: and reduction of work involved in the cycle.

In order to more clearly understand the presen-t inven- 1- N0 intercoolilg 635 80=508 tion, the thermodynamic process will 'be compared with 2 With ini-,Grooming g 34 80=5 67 that of a straight compression cycle. 6 67 An example of a one-stage compression, as seen in Increase ill GCGDOY =5468=131 OI 31% Fig. 3, with conditions as 40 F. evaporator and 100 F. condenser `using Freon-lZ as refrigerant is as follows: Net Increase m emclency=-31 80=248% 1. Work =H1-H4=90.85-82.71=8.14 B.t.u./lb. 2. Refrigeration =H4-H2=82.7l-31.16=51.55 B.t.11./1b.

refrigeration 51.55 3. Coefment of performance----Work ---8 14 -6.35

As seen on the pressure-enthalpy diagram in Fig. 3, In view of the foregoing, it may be appreciated that this process of compression is from point H4 to point H1. 60 the present invention provides a heat pump having a Ordinarily this is an isentropic process which requires a refrigerant injection unit providing an intercooling process certain amount of work to be carried out. For this parwhich considerably increases its eiciency thereby making ticular case as set forth above in the example, 8.14 B.t.u. it more desirable for commercial usage. of work per pound of refrigerant is required. It will be understood that modications and variations The amount of work is reduced according to the presmay be eected without departing from the scope of the ent invention for the same amount of refrigeration by novel concepts of the present invention, but it is undercooling the compression process as it takes place thereby stood that this application is to be limited only by the obtaining a nal point H5 instead of point H1, on the scope of the appended claims. pressure-enthalpy diagram which closely follows the vapor The invention is hereby claimed as follows: saturation line or curve 45. Even through it is necessary l. In a heat pump including a compressor, an evapto use a portion of the refrigerant for the Vintercooling orator, a condenser, an expansion valve, a low pressure process and divert it from the evaporator, the net etiline between the compressor and evaporator, a rst high ciency is increased. pressure line between the compressor and condenser, and Before calculating the refrigeration accomplished by a second high pressure line between the condenser and the present invention, it is rst necessary to determine evaporator having the expansion valve therein, the imthe amount of refrigerant diverted to the refrigerant inpl'ovement of means connected between the lsecond high pressure line and the compressor receiving liquid refrigerant and being responsive to the compressing action of the compressor to increase the pressure of the liquid refrigerant and inject a predetermined amount of liquid refrigerant of increased pressure into the compressor.

2. In a heat pump including a reciprocating compressor, an evaporator, a condenser, an expansion valve, a low pressure line between the compressor and evaporator, a first high pressure line between the compressor and condenser, and a second high pressure line between the condenser and evaporator having the expansion valve therein, the improvement of means connected between the second -high pressure line on the inlet side of said expansion valve and the compressor receiving high pressure liquid refrigerant and being responsive to the compression stroke of the compressor to increase the pressure of the liquid refrigerant and inject a charge of the liquid refrigerant of increased pressure into the compressor.

3. In a heat pump including a compressor, an evaporator, a condenser, an expansion valve, a low pressure line between the compressor and evaporator, a first high pressure line between the compressor and condenser, and a second high pressure line between the condenser and evaporator having the expansion valve therein, the improvement of means connected between the second high pressure line on the inlet side of said expansion valve and the compressor receiving high pressure liquid refrigerant and being responsive to the compressing action of the compressor to increase the pressure of the liquid refrigerant and inject a charge of the liquid refrigerant of in'- creased pressure into the compressor, and means on said first means for adjusting the quantity of said charge.

4. In a heat pump including a compressor having a compression chamber, an evaporator, a condenser, an eX- pansion valve, a low pressure line between the compressor and evaporator, a rst high pressure line -between the compressor and condenser, and a second high pressure line between the condenser and evaporator having the expansion valve therein, the improvement of means connected between the `second high pressure line and the compression chamber of the compressor being responsive to the compressor to inject a predetermined amount of liquid refrigerant into the compressor, said means comprising a casing having a charge chamber therein, said second high pressure line connected to said chamber, a one-way valve between said chamber and said condenser, a line interconnecting the chamber to said compressor, a second one-way valve between said chamber and said compressor, and a piston in said casing responsive to the compressing action of said compressor for forcing the charge in said chamber into said compressor.

5. In a heat pump including a reciprocating compressor having a compression chamber, an evaporator, a condenser, an expansion valve, a low pressure line between the compressor and evaporator, a first high pressure line between the compressor and condenser, and a second high pressure line between the condenser and evaporator having the expansion valve therein, the improvement of means connected between the second high pressure line and the compression chamber of the compressor being responsive to the compressor to inject a predetermined amount of liquid refrigerant into the compressor, said means comprising a casing having a charge chamber therein, said second high pressure line connected to said chamber, a one-way valve between said chamber and said condenser, a line interconnecting the chamber to `said compressor, a second one-way valve between said chamber and said compressor, and a floating piston in said casing responsive to said compression stroke of the compressor for forcing the charge in said chamber into said compressor.

6. A heat pump comprising a reciprocating compressor, an evaporator, a condenser, a pressure actuated refrigerant injection unit, and a refrigerant circulating in said pump, a first high pressure line connecting the compressor and condenser, a low pressure line connecting the evaporator and compressor, -a second high pressure lint? connecting the condenser and` evaporator, an expansion valve in said second high pressure line, and a high pres-` sure line connecting said vsecond high pressure line and said injection unit, said injection unit being responsive to the compression stroke of said compressor to increase the pressure of refrigerant received therebyy and inject' a'v charge of said refrigerant of increased pressure into the compressor.

7. A heat pump comprising a compressor having a compression chamber, an evaporator, a condenser, a refrigerant, aline connecting the compressor and condenser for carrying high pressure gas refrigerant to said condenser, a line having an expansion valve therein connecting the condenser and evaporator for carrying high pressure liquid refrigerant between said condenser and expansion valve and low pressure refrigerant between said expansion Valve and said evaporator, a line connecting said evaporator and compressor for returning Ilow pressure gas refrigerant to said compressor, and a refrigerant injection unit connected between the line connecting the condenser and evaporator and the compression chamber of the compressor for increasing the pressure of the high pressure liquid and for injecting a charge of same into said compressor during the compression stroke, said refrigerant injection unit including a stepped casing having a stepped piston therein, a line connecting one end of said piston directly with said compressor and a line connecting the other end with the compressor when the compressor is engaged in the compression stroke.

8. A heat pump comprising a compressor having a compression chamber, an evaporator, a condenser, a refrigerant, a line connecting the compressor and condenser for carrying high pressure gas refrigerant to said condenser, a line having an expansion valve therein connecting the condenser and evaporator for carrying high pressure liquid refrigerant between said condenser and expansion valve and low pressure refrigerant between said expansion valve and said evaporator, a line connecting said evaporator and compressor for returning low pressure gas refrigerant to said compressor, and a refrigerant injection unit connected between the |line connecting the condenser and evaporator and the compression chamber of the compressor for increasing the pressure of the high pressure liquid and for injecting a charge of same into said compressor during the compression stroke, said refrigerant charging unit including a stepped casing having a stepped piston therein, a line connecting the larger end of said piston directly with said compressor and a line connecting the smaller end of the piston with the cornpressor during the compression stroke.

9. A heat pump comprising a compressor having a compression chamber, an evaporator, a condenser, a refrigerant, a line connecting the compressor and condenser for carrying high pressure gas refrigerant to said condenser, a line having an expansion valve therein connecting the condenser and evaporator for carrying high pressure liquid refrigerant between said condenser :and expansion valve and low pressure refrigerant between said expansion valve and said evaporator, a line connecting said evaporator and compressor for returning low pressure gas refrigerant to said compressor, and a refrigerant injection unit connected between the line connecting the condenser and evaporator and the compression chamber of the compressor for increasing the pressure of the high pressure liquid and for injecting a charge of same into said compressor during the compression stroke, said refrigerant injection unit including a stepped casing having a stepped piston therein, a line connecting the larger end of said piston directly with said compressor and a line connecting the smaller end of the piston with the cornpressor during the compression stroke, and means in said casing acting on said piston to return it to normal position after the injection stroke.

7 10. A heat pump comprising a compressor having a compression chamber, an evaporator, a condenser, a refrigerant, al line connecting the compressor and condenser for carrying high pressure gas refrigerant to said condenser, a line having an expansion valve therein connectingthe condenser and evaporator for carrying high pressure liquid refrigerant to said evaporator, a line connecting said evaporator and compressor for returning low pressure gas refrigerant to said compsor, and a refrigerant injection unit including a casing having large and small contiguous stepped bores and a movable piston therein having large and small stepped portions, lines communicating both ends of the piston to the compressor, a check valve in the line communicating the small end of the piston with the compression chamber of the compressor permitting refrigerant ow only from the injection unit to the compressor, a line communicating the small end of the piston with the line carrying the high pressure liquid refrigerant, and a check valve in said last line permitting refrigerant ow only to the injection unit, whereby said piston is activated by the compressor during the compression stroke to inject a measured charge of refrigerant into said compressor.

1l. A heat pump comprising a compressor having a compression chamber, an evaporator, a condenser, a refrigerant, a line connecting the compressor and condenser for carrying high pressure gas refrigerant to said condenser, a line having an expansion valve therein cone necting the condenser and evaporator for carrying highpressure liquid refrigerant to said evaporator, a line connecting said evaporator and compressor for returning low pressure gas refrigerant to saidrcompressor, and ai refrigerant injection unit including a casing having large and small contiguous stepped bores and a movable piston therein having large and small stepped portions, lines communicating both ends of the piston to the compressor, a check valve in the line communicating the small end of the piston with the compression chamber of the compressor permitting refrigerant oW only from the injection unit to the compressor, a line communicating the small end of the piston with the line carrying the high'pressure liquid refrigerant, and a check valve in said last line permitting refrigerant flow only to the injection uni-t, and means for limiting the movement of said piston to control the quantity of the measured charge, whereby said piston is activated by the compressor during the compression stroke to inject a measured charge of-refrigerant into said compressor.

References Cited in the le of this patent UNITED STATES PATENTS 268,347 Wood et al Nov. 28, `1882 730,495 Vollmann .Tune 9, 1903 2,577,107 Cooper Dec. 4, 1951 2,776,542 Cooper Ian. 8, 1957 

